Such a cutting tool, known from Federal Republic of Germany Offenlegungsschrift No. 30 37 576 has the advantage that the cutting insert can be manufactured simply, that it requires only a very small cutting insert volume and, furthermore, it allows for fastening of the cutting insert, which improves the machining process with respect to conventionally known metal working arrangements. In particular, the cutting insert of this cutting tool does not require complicated inclined engagement recesses for the clamping jaw, such as provided, for instance, in Federal Republic of Germany Offenlegungsschrift No. 25 09 226.
For a series of application cases, especially for boring tools, whereby usually the entire cutting edge is in fastening engagement, it is necessary that there are not provided any construction components, such as, for instance, clamping jaws, as indicated in DE-OS No. 30 37 576, because they would hinder the free machining process. The object of the present invention is, therefore, to provide an initially described tool such that, in addition to its advantages, it also ensures a further improved machining process.
According to the present invention, the object is attained whereby in the area of the joint longitudinal edge of the cutting face, there is provided a continuous groove extending over the entire length of the cutting insert, whereby one of its side walls serves as a contact surface for the relief-cut pressure-feed and support surface of the recess, and the corresponding other side wall forms the support area of a clamping jaw, and it is configured to be disposed in a diagonal groove of the tool shaft.
According to the invention, there is provided a groove in the cutting insert in order to achieve a recessed configuration with the clamping jaw. This groove, however, is configured much simpler than in the previously-known configurations. It is a simple continuous, for example, rectangular groove whereby, because of the reversibility, preferably this groove is configured symmetrical to the corresponding diagonal of the cutting insert.
The decisive difference between known reversible cutting inserts with an engagement groove for the clamping jaw, whereby the same engagement groove functions in both work positions of the cutting insert, and where the other one of the two side surfaces of the clamping jaw is acted upon only alternatingly, consists in that the cutting insert does not make contact in the area of the cutting face. In the cutting tool according to the invention, the pressure-feed and support surface of the tool shaft is instead configured relief-cut, so that an upper rib-shaped protruding section makes contact with the side wall of the groove of the cutting insert which is not needed as a support for the clamping jaw. Among others, this has the advantage that, independent of the size and the configuration of the machining guide stage, there is always present the same back pressure surface for jointly absorbing the cutting pressure.
In a further aspect of the invention, it is possible to provide that the clamping jaw almost completely fills the diagonal groove. Especially with longer cutting parts, it can also be provided that there are arranged several clamping jaws.
In contrast to known utilized cutting inserts with respect to the longitudinal axis of the cutting insert which are not inclined, a special advantage of the continuous groove according to the invention is that it permits the cutting insert to be clamped in any desirable longitudinal position in the recess of the tool shaft. With the help of one and the same cutting plate, it is thereby possible to achieve random fine tuning with respect to the cutting depth (in the case of boring tools) and to avoid having to manufacture exactly adjusted cutting inserts for certain finished dimensions. In order to avoid a sliding shifting of the position of the cutting insert caused by the cutting pressure, the back pressure and support surface of the cutting insert should make contact with an adjustment element. By means of shifting, the cutting insert is therefore adjusted in the recess of the tool shaft and is then clamped in the desired position by means of the clamping jaw.
Furthermore, the guidance-like configured plate lodgement also allows bringing the cutting insert into the smallest possible position, clamping it, and shifting it to the desired position via the adjustment element which can be configured as a release element. It is not necessary to again reclamp the clamping jaw. The principal cutting insert remains in its position during the shifting of the cutting plate. In order to assure this in each case, it is necessary that the pressure point of the adjustment element, preferably configured as a small-threaded adjustment screw, is positioned before the gripping point of the clamping element.
It has already been described above that especially for boring tools, preferably, the clamping or fitting groove is symmetrically configured. In the case of boring especially deep boreholes, the end-user wishes to use a tool having two or more cutting edges, in order to avoid running off center of the cutting tool, whereby the rough plate(s) is (are) running in an axial direction which, however, with respect to the subsequent finishing plate(s) cuts (cut) smaller in the radial direction. The subsequent finishing plate(s) finishes (finish) the bore diameter. In the standard case, axial and radial movements of 0.3 to 0.5 mm are sufficient between the turnplates. This kind of configuration can be achieved in this invention by means of providing different sized symmetrical clamping grooves, and also by means of inserting assymetrical clamping grooves without requiring any alteration of the support tool.
Further advantages, characteristics and features of the invention will be seen from the following description of several exemplified embodiments, as well as from the drawings which follow